For a liquid crystal panel that functions as a quarter-wave plate, it is known to provide a configuration in which the liquid crystal panel is tilted with respect to the optical axis by an angle equal to the angle (pretilt angle) that the long axis direction of liquid crystal molecules makes with the glass substrate (for example, refer to patent document 1). By tilting the liquid crystal panel in this manner, the long axis direction of the liquid crystal molecules can be oriented at right angles to the optical axis, and the liquid crystal panel can thus be made to function as a perfect quarter-wave plate.
It is also known to provide a configuration in which two liquid crystal layers are formed using three glass substrates, one liquid crystal layer being formed as an aberration correcting layer and the other as a quarter-wave plate, and the liquid crystal panel with its rubbing direction oriented at an angle of 45 degrees relative to the rubbing direction of the aberration correcting liquid crystal layer is placed perpendicular to the optical axis (refer, for example, to patent document 2).
Patent document 1: Japanese Patent Publication No. 3142251 (page 3 and FIG. 2)
Patent document 2: Japanese Unexamined Patent Publication No. 2001-34996 (page 29 and FIG. 21).